This invention relates generally to the art of electronic test apparatus, and more particularly, concerns the testing of the various junctions of semiconductor elements.
With the significant increase in the use of semiconductor devices in electronic circuits has arisen a need for test apparatus whichh can accurately determine the operating condition of the semiconductor. A wide range of circuit elements can be included under the generic term "semiconductors", including diodes, transistors and controlled gate devices. Furthermore, many complicated semiconductors have been devised in recent years using multiple junctions and specialized gating arrangements.
There are currently available many devices which in one manner or another attempt to test the operation of semiconductors and provide a reliable indication thereof. As an example, special curve tracer attachments to oscilloscopes are well-known for the testing of certain transistors. Other test apparatus, some very complicated and expensive for testing of complex semiconductor devices, and others rather simple for testing of single junction semiconductors, are also available. However, a common fault of present semiconductor test apparatus is that they are unable to test the operation of a semiconductor while the semiconductor is physically connected in a low impedance circuit, which is often the case. Thus, the testing of semiconductors in such low impedance circuits requires the physical disconnection or removal of the semiconductor from the circuit. Although not critical in some instances, the necessity of physical disconnection of individual semiconductors from their operational circuits, before testing thereof, results in significant additional time and expense in repair of electronic circuits, and may well prevent full and complete investigation of possible semiconductor damage or failure in complex circuits.
In view of the above, it is a general object of the present invention to provide a semiconductor test apparatus which overcomes the disadvantages of the prior art discussed above.
It is another object of the present invention to provide such a test apparatus which is capable of testing semiconductors while they are physically connected in an electronic circuit.
It is a further object of the present invention to provide such a test apparatus which provides a visual indication of the operating condition of a semiconductor.
It is yet another object of the present invention to provide such a test apparatus which may be conveniently operated from 120 volt AC power.
It is a still further object of the present invention to provide such a test apparatus which is capable of accurately testing semiconductors which are physically connected in a low impedance circuit.
It is another object of the present invention to provide such a test apparatus which is capable of testing individual junctions in a semiconductor.
It is a further object of the present invention to provide such a test apparatus which provides signals for connection to the horizontal and vertical inputs of a standard oscilloscope, the pattern on the oscilloscope derived from such signals providing an indication of the operating condition of that semiconductor junction connected between the test leads of the apparatus.
It is yet another object of the present invention to provide such a test apparatus having a relatively low output impedance presented to its test leads.